Numanouchi Formation

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Numanouchi Formation Iwai, 1950

Type locality: Numanouchi, Taira, Iwaki city, Fukushima prefecture
Coherent formation
southern Yezo Forearc basin (Jobanoki basin)
early Miocene (16.5 - 16.3 Ma, Diatoms)

Sedimentary facies: Marine
Sedimentary facies: Lower shoreface - Inner shelf
Lithofacies: Silty sandstone, Tuffaceous silty sandstone
Sedimentary structures: Bioturbation

Thickness: ca. 20 - 70 m
Lower limit: Conformity (Kamitakaku Formation)

Takaku Group
[ Upper ]
~~~~~~~~~~~~~~
Shimotakaku Formation
--------------
Numanouchi Formation
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Kamitakaku Formation
~~~~~~~~~~~~~~
[ Lower ]

Takaku Group
[ Upper ]
?--?--?--?--?-
Kokozura Formation
?--?--?--?--?-
[ Lower ]

------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown

Distribution: Numanouchi, Taira, Iwaki city, Fukushima pref.; Ide river, Tateishi, Naraha city, Futaba county, Fukushima pref.
Fossils: Shellfishes
Fossils (Diatoms): Actinocyclus ingens, Actinoptychus senarius, Aulacoseira spp., Coscinodiscus marginatus, Kisseleviella carina, Paralia sulcata, Stephanogonia hanzawae, Stephanopyxis, Thalassionema nitzschioides

Ando et al. (2011) Jour. Geol. Soc. Japan, vol.117, Supplement, pp.49-67 DOI
Kubo et al. (2002) Geology of the Kawamae and Ide District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 136p. (in Japanese with English abstract 6p.)